Abstract

BACKGROUND:

Denervation atrophy is one factor contributing to suboptimal motor recovery following major nerve repair. The hypertrophic effects of anabolic steroids may have a potential role in improving reinnervated muscle strength after delayed repair.

METHODS:

Forty-five immature female Sprague-Dawley rats underwent three surgeries and final testing. The tibial nerve was transected in the hind limb of the experimental (n = 13) and control (n = 14) animals and exposed, but not transected in the sham (n = 15) group animals. Three months later, once denervation atrophy was established, all transected nerves underwent repair using an autograft from the contralateral limb. After waiting an additional month to allow axonal regeneration to the gastrocnemius muscles, the rodents were implanted with a subcutaneous infusion pump. For the experimental group, nandrolone was administered over the next 30 days via this pump, while the control and sham group pumps were filled with carrier only.

RESULTS:

Final testing, 6 weeks later, showed improved muscle contraction strength in the steroid-treated animals (72% of sham group strength) compared to control animals (57% of sham group strength, p < 0.5). A trend towards increased weight and muscle belly diameter in the steroid-treated group was not statistically significant.

CONCLUSIONS:

These findings support the potential role of anabolic steroids in improving recovery of atrophic muscle after delayed reinnervation.

Muscle belly weight was statistically higher in the sham group compared to the experimental and control groups. The experimental group averaged a higher muscle belly weight than the control group, but this did not reach statistical significance

Individual muscle fiber cross-sectional area (CSA) average was higher for the sham group compared to the experimental and control groups (p < 0.05). There was a trend for larger cross-sectional areas for the experimental group compared to the control group, but this was not statistically significant